PF 320sqft Clean&Clear Plus Cartridge Filter Clean and Clear® Plus Filters have a corrosion resistant injection molded filter tank featuring superior strength and reliability. The cartridge assembly uses four easy to clean, non-woven, polyester cartridges. Each filter is supplied with a bulkhead union set for easy installation. An Eco Select™ Choice: Water flows very efficiently through Clean and Clear® Plus Filters filters allowing the use of smaller pumps or lower pump speeds to minimize energy use. And when consumers rinse cartridges rather than backwash, they can significantly reduce water use, too. Features NSF listed Superior strength Large filter area for increased dirt capacity 1-1/2 in., 100% drain clean-out port Continuous High Flow™ internal air relief* Base and plumbing kits now available Injection molded tank Balanced hydraulic flow Tension Control™ clamp 100% factory tested Black bulkhead unions High Flow manual air relief valve